Coated abrasive belt



May 12, 1953 w. G. NUESSLE 2,637,956 COATED ABRASIVE BELT Filed March28, 1952 max/Wm? Patented May 12, 1953 COATED ABRASIVE BELT Walter G.Nuessle, St Paul, Minn, assignor to Minnesota Mining & ManufacturingCompany, St. Paul, Minn., a corporation of Delaware Application March28, 1952, Serial No. 279,037

3 Claims.

This invention relates to coated abrasive articles, and, moreparticularly, to such articles in the form of an endless belt. The useof coated abrasive belts has been extended markedly in recent years,partially through the development of improved grinding devices whichinclude a contact roll for resiliently, yet firmly, supporting theabrasive belt againstthe workpiece while the former is moving at highspeeds. Such uses of abrasive belts have quite largely been confined toabrading substantially fiat surfaces, such as steel sheets, fiat glass,glass edges, and the like.

An object of this invention is the provision of a coated abrasive beltthat may be employed not only to abrade and polish fiat surfaces butalso may be supported upon a contact roll or platen to abrade and polishcurved surfaces of small radii, such as, for example, the recessed areasof cutlery, trigger guards, and the fillets of jet blades, where theedge of the conventional abrasive belt would undercut or rapidly becomefrayed.

Coated abrasive belts known to the art are provided with straight edges.I have found that a workpiece having a curved surface of a small radiusmay be abraded or polished in a highly satisfactory manner by the use ofcoated abrasive belts having scalloped or pinked edges, as hereinafterset forth. A further advantage of my improved belt lies in the fact thatthe same belt may be employed in grinding both flat and curved surfaces,and thus it is not necessary to change the belt used in grinding thefoil surface of a jet blade when it is desired to abrade the curved rootsection of the blade.

The invention will be readily understood from the following descriptionin connection with the accompanying drawing, in which:

Figure 1 is a perspective view of a portion of the improved abrasivebelt mounted upon a contact roll, forming a part of a grinding device(not shown) and in position to abrade the curved root section of a jetblade as the workpiece;

Figure 2, a plan view or a portion of my improved coated abrasive belt;

Figure 3, an enlarged front elevational view, partly in section, of theelements shown in Figure 1;

Figure 4, an enlarged side elevation of my improved belt mounted upon acontact roll, with the workpiece removed.

Referring to the drawing, in Figures 1 and 3, my improved abrasive beltI is shown mounted upon a contact or presser roll II in position toabrade the curved fillet ll of a jet blade 13. The contact roll ispreferably provided with sloping or tapered peripheral edges l4, and isotherwise of conventional construction. It has a somewhat resilientsurface to afford a firm, yet yielding, support for the abrasive beltwhen the latter is engaged with the workpiece. The contact roll H may beof the type disclosed in Herchenrider Patent No. 2,145,418 of January31, 1939. The contact roll H is one element of a conventional grindingdevice (not shown) of the type in which a flexible abrasive belt istrained over a contact roll and a driven roll and on which the belt maybe driven at high speeds. Grinding and polishing devices of the generaltype disclosed in the above-mentioned Herchenrider patent are suitablefor use with my improved abrasive belt. The belt may also be employedwith a permanent shaped back-up support, such as aformed platen.

The belt I!) comprises a flexible backing l5 coated upon one surfacewith an adhesive binder I6 and carrying a layer 1'! of abrasiveparticles embedded in the binder. The backing may be formed of cloth,such as stretched, pre-shrunk drill cloth, vulcanized fiber, paper,combinations of cloth, fiber or paper, or similar flexible,dimensionally stable material. The adhesive binder may comprise one ormore coatings of glue or of a synthetic resin, such as modified phenolicresins or a drying-oil-modified alkyl resin, for example, of the typedisclosed in the Guth Patent No. 2,202,756, or of combinations of glueand resin coatings. The abrasive grits are those previously employed inthe coated abrasive industry, such as silicon carbide or aluminum oxide.Endless belts may be made from the coated and cured sheet material byslitting it to the proper width and skiving and splicing together theends of a strip of the desired length, in accordance with well-knownpractice.

After the coated web has been cured and slit to strips of the desiredwidth, and preferably before the ends of the strips have been spliced,the coated strips are passed through a pinking device to cut out, in oneor both edges of the strips, suitably shaped indentations l8, regularlyspaced between intervening ridges l9. The size and spacing of theindentations l8 may vary in difierent belts, dependin upon suchvariables as thewidth of the belt, the diameter of the contact roll uponwhich the belt is to be mounted, the shape and radius of curvature ofthe workpiece and the speed of belt travel. At higher speeds a belthaving fewer indentations for a given length can be satisfactorilyemployed than when the belt is driven at slower speeds. It isparticularly important that the ridges or scallops [3 are of such shapeand size that they will not overlap each other when bent over at anglesapproaching 90 when engaged with the work. Otherwise the workpiece maybe marred or abraded irregularly. The curved fillets of jet blades, asshown in the drawing, have been satisfactorily abraded with a belt of aninch in width (from crest to crest) and mounted on a contact roll of 2%;inches in diameter. This belt was provided with four indentations, of adepth of approximately of an inch, per linear inch. The distance betweenadjacent lands was approximately of an inch, and, as shown, the shape ofthe ridge l5 and intervening valleys 01' indentations l8 approximatedthe curve of a sine wave. On a wider belt to be used on a larger contactroll, the indentations would preferably be deeper than of an inch.Likewise, the shape of the indentations and intervening ridges may bemodified and they may be approximately square or oblong, or may besaw-toothed in shape.

As shown in Figures 1, 3 and 4, as the im proved belt passes over thecontact roll and bears against the workpiece, the lands or ridges l3coated with abrasive particles are bent from the plane of the centralportion of the belt and conform to the curvature of the work. Asindicated in the drawing, it is essential that the ridges be so shapedand spaced that they do not overlap each other when bent again-st thecurved Workpiece. If both edges of the belt are scalloped, a ridge !9 onone edge is preferably disposed opposite to a valley IS on the otheredge.

While the invention is preferably employed in abrasive articles, in theform of coated abrasive belts, it is apparent that my improved abrasivematerial has utility in the form of discs, fiat sheets or strips, etc.

Having described various embodiments of my invention for purposes ofillustration, but with out intent to be limited thereto, what I claim isas follows:

1. A flexible abrasive belt suitable for the abrading of curved surfacescomprising a flexible, dimensionally stable backing, an adhesive coatingon one surface of said backing, and a multiplicity of abrasive particlesembedded in said adhesive coating, at least one edge of said belt beingprovided with a series of evenly shaped and spaced indentations, theintervening ridges being coated on one surface thereof with abrasiveparticles and being spaced in such manner that they do not overlap eachother when bent to the work.

2. A coated abrasive belt suitable for the abrading of curved surfacescomprising a waterresistant, dimensionally stable backing, an adhesivebinder coated on one surface of said backing and a multiplicity ofabrasive particles embedded in said binder, at least one edge of saidbelt being scalloped to provide indentations and intervening lands, theedges of said lands and indentations forming a curve of the natureof asine wave, the lands being coated on one surface thereof with abrasiveparticles.

3. A coated abrasive belt comprising a flexible, water-resistant,dimensionally stable backing, an adhesive coating on one surface of saidbacking, and abrasive particles embedded in said adhesive coating, bothedges of said belt being provided with regularly spaced and shapedindentations, the ridges intervening said indentations being coated onone surface thereof with abrasive particles and the ridges on one edgeof said belt being disposed opposite to the valleys on the other edge ofsaid belt.

WALTER G. NUESSLE.

N 0 references cited.

